From bddabeb71f3fc2577d7576251507f36320cecdb1 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Fri, 20 Apr 2018 10:24:04 +0200 Subject: [PATCH] vfio: ccw: process ssch with interrupts disabled commit 3368e547c52b96586f0edf9657ca12b94d8e61a7 upstream. When we call ssch, an interrupt might already be pending once we return from the START SUBCHANNEL instruction. Therefore we need to make sure interrupts are disabled while holding the subchannel lock until after we're done with our processing. Cc: stable@vger.kernel.org #v4.12+ Reviewed-by: Dong Jia Shi Acked-by: Halil Pasic Acked-by: Pierre Morel Signed-off-by: Cornelia Huck Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- drivers/s390/cio/vfio_ccw_fsm.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c index c30420c517b1..e96b85579f21 100644 --- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -20,12 +20,12 @@ static int fsm_io_helper(struct vfio_ccw_private *private) int ccode; __u8 lpm; unsigned long flags; + int ret; sch = private->sch; spin_lock_irqsave(sch->lock, flags); private->state = VFIO_CCW_STATE_BUSY; - spin_unlock_irqrestore(sch->lock, flags); orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm); @@ -38,10 +38,12 @@ static int fsm_io_helper(struct vfio_ccw_private *private) * Initialize device status information */ sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND; - return 0; + ret = 0; + break; case 1: /* Status pending */ case 2: /* Busy */ - return -EBUSY; + ret = -EBUSY; + break; case 3: /* Device/path not operational */ { lpm = orb->cmd.lpm; @@ -51,13 +53,16 @@ static int fsm_io_helper(struct vfio_ccw_private *private) sch->lpm = 0; if (cio_update_schib(sch)) - return -ENODEV; - - return sch->lpm ? -EACCES : -ENODEV; + ret = -ENODEV; + else + ret = sch->lpm ? -EACCES : -ENODEV; + break; } default: - return ccode; + ret = ccode; } + spin_unlock_irqrestore(sch->lock, flags); + return ret; } static void fsm_notoper(struct vfio_ccw_private *private, -- 2.20.1